docs: def ls(path):
      """List files on HDFS.
  
      :param path: A string (potentially with wildcards).
      :rtype: A list of strings representing HDFS paths.
      :raises: IOError: An error occurred listing the directory (e.g., not available).
      """
      rcode, stdout, stderr = _checked_hadoop_fs_command('hadoop fs -ls %s' % path)
      found_line = lambda x: re.search('Found [0-9]+ items$', x)
      out = [x.split(' ')[-1] for x in stdout.split('\n')
             if x and not found_line(x)]
      return out